Print Email Facebook Twitter Reliability of System Identification Techniques to Assess Standing Balance in Healthy Elderly Title Reliability of System Identification Techniques to Assess Standing Balance in Healthy Elderly Author Pasma, J.H. Engelhart, D. Maier, A.B. Aarts, R.G.K.M. Van Gerven, J.M.A. Arendzen, J.H. Schouten, A.C. Meskers, C.G.M. Van der Kooij, H. Faculty Mechanical, Maritime and Materials Engineering Department Biomechanical Engineering Date 2016-03-08 Abstract Objectives System identification techniques have the potential to assess the contribution of the underlying systems involved in standing balance by applying well-known disturbances. We investigated the reliability of standing balance parameters obtained with multivariate closed loop system identification techniques. Methods In twelve healthy elderly balance tests were performed twice a day during three days. Body sway was measured during two minutes of standing with eyes closed and the Balance test Room (BalRoom) was used to apply four disturbances simultaneously: two sensory disturbances, to the proprioceptive and the visual system, and two mechanical disturbances applied at the leg and trunk segment. Using system identification techniques, sensitivity functions of the sensory disturbances and the neuromuscular controller were estimated. Based on the generalizability theory (G theory), systematic errors and sources of variability were assessed using linear mixed models and reliability was assessed by computing indexes of dependability (ID), standard error of measurement (SEM) and minimal detectable change (MDC). Results A systematic error was found between the first and second trial in the sensitivity functions. No systematic error was found in the neuromuscular controller and body sway. The reliability of 15 of 25 parameters and body sway were moderate to excellent when the results of two trials on three days were averaged. To reach an excellent reliability on one day in 7 out of 25 parameters, it was predicted that at least seven trials must be averaged. Conclusion This study shows that system identification techniques are a promising method to assess the underlying systems involved in standing balance in elderly. However, most of the parameters do not appear to be reliable unless a large number of trials are collected across multiple days. To reach an excellent reliability in one third of the parameters, a training session for participants is needed and at least seven trials of two minutes must be performed on one day. Subject OA-Fund TU Delft To reference this document use: http://resolver.tudelft.nl/uuid:4d1395c6-bf7e-4fd3-b6c7-10102612e542 Publisher Public Library of Science ISSN 1932-6203 Source https://doi.org/10.1371/journal.pone.0151012 Source PLoS ONE, 11 (3), 2016 Part of collection Institutional Repository Document type journal article Rights © 2016 The Author(s)This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited Files PDF Pasma_2016.pdf 1.61 MB Close viewer /islandora/object/uuid:4d1395c6-bf7e-4fd3-b6c7-10102612e542/datastream/OBJ/view